The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 27, 2010
Filed:
Dec. 12, 2006
Seiji Sakai, Tokyo, JP;
Toshiyuki Yoneda, Tokyo, JP;
Seiji Sakai, Tokyo, JP;
Toshiyuki Yoneda, Tokyo, JP;
Mitsubishi Electric Corporation, Tokyo, JP;
Abstract
A surface light source device according to the invention includes a housing having an opening portion on at least one face, an LED light source held by one face of the housing opposing the opening portion, and a light guiding plate arranged at a position so as to cover the opening portion and the LED light source. The light guiding plate includes a recess provided at a position corresponding to the LED light source for storing a part of the LED light source. A light quantity adjusting means is provided at a bottom part of the recess for adjusting light from the LED light source. The light quantity adjusting means includes a reflection sheet having a reflection function and a transmission function in which a total light transmittance t satisfies t≧πrcos θ/{(1−cos θ)(S−πr)}, supposing that an average radius is defined as r, a distance from the LED light source is defined as H, a light-emitting area of the LED light source is defined as S, and a total light quantity is defined as L.